Demon Knight is a text based adventure game.
The beautiful maiden has been taken by the aforementioned knight and, as the player, you must explore the terrain to find and rescue her.
As you progress you must collect useful objects, (not all objects are useful so don't overburden yourself with trash), vanquish foes, solve puzzles and so on.
Eventually you will meet the demon knight himself and you must defeat him to complete the game.
There are three single word commands, HELP, INVENTORY and QUIT. All other commands are limited to two words, GO EAST, KILL SKELETON, etc.